When the utility announces Stage 2, the first thing an operator wants to know is: how long will my site be dark? The published schedule does not answer that question. It answers a different one: how many megawatts will be shed nationally, and what block window has been assigned to your area. Those are not the same thing, and the gap between them is where capacity plans fail.
This article is about reading the schedule correctly. Not as a promise, but as a planning envelope — a published error budget you can size against, provided you understand what it does and does not commit to.
What the published schedule actually commits to
Eskom’s schedule interpretation page is explicit about the stage-to-megawatt mapping. Each stage allows a specific additional amount of national load to be shed:
Stage 1 allows for up to 1000 MW of the national load to be shed. Stage 2 allows for up to 2000 MW of the national load to be shed. Stage 3 allows for up to 3000 MW of the national load to be shed. Stage 4 allows for up to 4000 MW of the national load to be shed. Stage 5 allows for up to 5000 MW of the national load to be shed. Stage 6 allows for up to 6000 MW of the national load to be shed. Stage 7 allows for up to 7000 MW of the national load to be shed. Stage 8 allows for up to 8000 MW of the national load to be shed.
That is a national figure. It tells you nothing about your site. The per-site numbers are elsewhere on the same page: block length and the switching window.
For stages 1 to 4, most of the country runs 2-hour blocks. Eskom-supplied Johannesburg areas run 4-hour blocks to match City Power’s schedule. Each block gets an additional 30 minutes for switching, so a 2-hour block can mean up to 2.5 hours without power, and a 4-hour block up to 4.5 hours.
As stages climb, two things happen. The frequency of cuts increases, and from stage 5 upward the 2-hour blocks progressively double to 4 hours. The schedule states this directly:
Customers will expereince that the frequency of load shedding (ie the number of scheduled times per day) increases as higher Stages of load shedding are activated. Also, customers in areas that experience 2 hour blocks in Stages 1 to 4, will find that the length of these blocks is doubled progressively to 4 hours as stages 5 to 8 are activated.
So the schedule does commit to some things. It commits to a national MW figure per stage. It commits to a block design — 2 hours or 4 hours depending on area — and a 30-minute switching window. It commits to an escalation pattern where higher stages mean more frequent cuts and, from stage 5, longer blocks.
What it does not commit to is your site’s actual outage duration on any given day. The schedule page itself says the information is for “information purposes” only and that Eskom makes no representations or warranties regarding its accuracy or suitability. It also states that if more load needs to be shed than has been scheduled in Stages 1 to 8, National Control will instruct additional, unscheduled load shedding, meaning you may be shed outside your scheduled times.
That is not a criticism of Eskom. It is a description of what the document is. It is a national dispatch plan, not a service-level agreement with your clinic, your ISP node, or your workshop.
Why ‘SLA’ is a useful model but a dangerous assumption
An SLA has three components: a counterparty, a defined measurement method, and a remedy. The published load-shedding schedule has none of these for an individual site.
The counterparty is the System Operator, but the schedule explicitly states that the code does not subrogate any actions the System Operator may deem necessary in real time to ensure the security of the national power system, including prudently managing system operating reserves. In plain terms: the schedule can be overridden when the grid is at risk. That is the correct engineering decision. It is also the reason you cannot treat the schedule as a commitment.
The measurement method is national MW, not your site’s uptime. The remedy is nonexistent. There is no credit, no penalty, no escalation path for a site that was shed outside its block.
So why use the SLA frame at all? Because it forces you to ask the right questions. If this were an SLA, what would I measure? What would I size against? What would I do when it is breached? The answers to those questions are useful even when the SLA itself does not exist.
The only per-site numbers you can plan against
Strip away the national MW figures and the stage headlines. What remains that is specific to your site?
- Block length. Two hours in most areas during stages 1 to 4, four hours in Eskom-supplied Johannesburg areas, and progressively four hours from stage 5 upward in areas that normally run 2-hour blocks.
- Switching window. An additional 30 minutes per block, added to allow for safe switching of networks.
- Cut frequency at your stage. The schedule publishes expected cut counts per stage over a four-day or eight-day period. Stage 4, for example, means up to 12 cuts over four days in a 2-hour block area.
Everything else — whether your municipality follows the same block design, whether your specific feeder is shed on the published schedule, whether an unscheduled event adds a cut — is outside the published commitment. Eskom’s own page notes that municipality and metro schedules differ from Eskom schedules in design and detail, and that Eskom has no control over how municipalities or metros determine their own schedules.
If you are supplied by a metro, your block design is your metro’s, not Eskom’s. The switching window may differ. The cut counts may differ. The only way to know is to pull your metro’s schedule and read it as its own document.
A worked example: sizing a one-person clinic branch
This is a hypothetical. It uses only the published block lengths and switching window. It does not use vendor performance data, measured runtime, or any claim about what a specific battery or generator will do. The point is the method, not the numbers.
Suppose you run a one-person clinic branch on a 2-hour block area. You are on Stage 4. The schedule says up to 12 cuts over four days, 2 hours each, plus the 30-minute switching window. That is up to 2.5 hours per cut, and up to three cuts per day on average.
Your critical load is a vaccine fridge, a laptop, a router, and a light. You want to size battery runtime and generator fuel.
Step 1: Size for the longest block, not the average. The schedule allows 2.5 hours per cut at Stage 4. But Stage 5 doubles some blocks to 4 hours, and Stage 6 mixes 2-hour and 4-hour blocks. If you size for 2.5 hours, you are sized for Stage 4. If you want to survive Stage 6 without intervention, you need to size for 4.5 hours — the 4-hour block plus the switching window.
Step 2: Count the cuts, not just the hours. Three cuts per day at 2.5 hours each is 7.5 hours off per day. That is not the same as one 7.5-hour outage. Your battery has to recharge between cuts. If your recharge window is short — say, two hours between an evening cut and an overnight cut — your effective runtime is less than the nameplate capacity suggests. The schedule’s cut frequency is a planning input, not just the block length.
Step 3: Plan for the unscheduled cut. The schedule explicitly allows unscheduled load shedding when more load must be shed than Stages 1 to 8 provide. That means your worst case is not the published block. It is the published block plus an additional cut that you did not plan for. For a one-person site, the manual fallback is usually a small generator or a second battery bank that can be brought online without intervention. The cost of that fallback is the price of not being surprised.
Step 4: Re-run the plan at the next stage up. A plan sized for Stage 2 is not a plan sized for Stage 6. The schedule’s own escalation rules — more frequent cuts, longer blocks from stage 5 — mean that your capacity plan should be expressed as a range, not a single number. At minimum, know what stage your current plan survives, and what stage it does not.
Two failure modes of reading the schedule as an SLA
Failure mode 1: Assuming the headline stage applies to your slot all day. The announced stage is a national figure. It can vary by time of day. A Stage 6 headline does not mean every hour is Stage 6. Your block’s times matter more than the headline. If you plan against the headline and your block lands in a lower-stage window, you are over-provisioned. If it lands in a higher-stage window, you are under-provisioned. The schedule publishes block times for a reason. Use them.
Failure mode 2: Assuming your municipality’s block design matches Eskom’s. Eskom’s page is clear that municipality and metro schedules differ in design and detail, and that Eskom has no control over how they are determined. If you are a metro customer, your block length, cut frequency, and switching window may all differ. Pull your metro’s schedule. Read it as its own document. Do not assume the Eskom page applies to you.
What the schedule is not
It is not a guarantee of outage duration. It is not a guarantee of cut frequency at your site. It is not a commitment that your municipality follows the same design. It is not a remedy if your site is shed outside its block.
It is a published planning envelope. It tells you the national MW figure, the block design for your area, the switching window, and the escalation pattern. Those are real numbers. They are enough to size a capacity plan, provided you treat them as inputs to a plan rather than promises to rely on.
The NRS 048-9 code of practice, which governs load reduction in South Africa, describes load shedding as a controlled intervention affecting a limited number of customers at a time, distinct from a blackout which happens without warning and can affect many or all customers for an unpredictable period. That distinction matters. Load shedding is controlled. It is not a blackout. But it is also not an SLA. It is a controlled intervention that can be overridden in real time to prevent a national blackout, and the code explicitly preserves that override.
For a one-person site, the useful planning unit is not the stage. It is the longest continuous outage the site must survive without intervention. That is a function of block length, switching window, and whether the site can be re-energised unattended. The national MW figure does not enter into it.
A planning checklist
- Confirm who supplies you. Eskom direct or a municipality/metro. The schedules differ. The block design may differ. The switching window may differ.
- Pull your own block times. Not the headline stage. Your area’s block times, for the current stage. The schedule publishes them by area.
- Size for the longest block your stage can produce, plus the switching window. At Stage 4 in a 2-hour block area, that is 2.5 hours. At Stage 6, it is 4.5 hours. Know which one you are sized for.
- Count the cuts, not just the hours. Recharge windows between cuts matter. Three 2.5-hour cuts in a day is not the same as one 7.5-hour outage.
- Plan for the unscheduled cut. The schedule allows it. Your plan should survive it without intervention, or have a manual fallback that does not require someone to be awake at 3 a.m.
- Treat any stage change as a schedule change, not a breach. The stage can change with a few hours’ notice. Your plan should have a defined response to a stage change, not a complaint.
FAQ
Does the published schedule guarantee my site will be off for the full block? No. The schedule publishes block length and a switching window. It does not guarantee that your site is shed for the full block, or that it is shed at all. It also allows unscheduled load shedding when more load must be shed than Stages 1 to 8 provide.
My metro publishes a different schedule. Which one applies to me? Your metro’s schedule applies to you if your metro supplies you. Eskom’s page states that municipality and metro schedules differ in design and detail, and that Eskom has no control over how they are determined. Pull your metro’s schedule and read it as its own document.
How do I know what stage my area is on right now? The current stage is displayed on Eskom’s main website and load-shedding site, and on the MyEskom app. Third-party apps republish the same data. Eskom notes that it cannot guarantee third-party providers are using the latest data, but that they can be a useful alternative service.
What is the difference between load shedding and load reduction? Load shedding is a national, rotational intervention declared by stage. Load reduction is a local intervention to protect overloaded infrastructure, typically published by feeder or suburb. They are different schedules with different triggers. If your power is off on a clockwork schedule while the rest of the country is on, you are likely looking at load reduction, not a stage.
Should I size my battery for the headline stage or the block length? Size for the longest block your stage can produce, plus the switching window. The headline stage is a national MW figure. The block length and switching window are the per-site numbers. If you want to survive a stage change without intervention, size for the next stage up as well.
The bottom line
The published load-shedding schedule is a planning envelope, not an SLA. It gives you a national MW figure per stage, a block design for your area, a 30-minute switching window, and an escalation pattern. Those are enough to size a capacity plan. They are not enough to promise your site will be dark for exactly 2.5 hours on a given day.
Read the schedule for what it commits to. Plan for what it does not. And when the stage changes, treat it as a schedule change, not a breach. The grid is not your counterparty. It is a system you are planning around.